Electrical Overcharging

[FWB]

Originally Posted by Maurice Butler

there is a reason you can by replacement lucas smoke: http://www3.telus.net/bc_triumph_registry/smoke.htm

someone should start offering pre-melted wiring harness' for that original look.

[zzmac]

Drove the car yesterday and gauge was showing about 25-27. I brought my multimeter with me and checked it a few times and everytime it was at 14.5. Today I took the car out and the gauge was showing 14-15. So it must be a wonky gauge.

[DougD]

A voltmeter reads VOLTS, an ammeter reads AMPS.

The ammeter reading will vary by the load imposed on the circuit. Were your fans running? Headlights on? Anything else that cycles on/off or operates intermittently?

[patrickt]

Originally Posted by DougD

A voltmeter reads VOLTS, an ammeter reads AMPS.

The ammeter reading will vary by the load imposed on the circuit. Were your fans running? Headlights on? Anything else that cycles on/off or operates intermittently?

Assuming his car is wired normally, the ammeter will sit between the battery and the entire system's load and alternator. Increasing or decreasing the load should not affect the current running through the ammeter if the alternator/VR are performing properly -- and certainly will not make the ammeter point over in the plus direction. He really ought to buy that inductive ammeter of mine that I show in my previous post. It's a hundred bucks well spent. It sounds like he might just have a misbehaving gauge, and seeing a "normal" volt reading doesn't really tell you too much about current flow. Putting an inductive gauge on the wire would tell him for sure. Not to mention how cool it is to capture the intitial draw of heavy items, like fan motors, when they come on. MSD boxes usually have their feed sit on the "battery" side of the ammeter, though -- and they make a big deal about that in their instructions. Big stereos sometimes sit there too. But it boils down to either his gauge is broken, or the current is going somewhere over to the battery side of the ammeter's circuitry.

[strictlypersonl]

Pat's right, but another possibility is that there is something (like the fan) in the circuit that was wired outside of the ammeter. In that case, the ammeter will show a constant "charge" to compensate for the draw of the fan.

[patrickt]

... or, if the MSD Box is wired up with their recommended Noise Filter #8830, which is just a big-ass capacitor, and that capacitor has a case of "intermittent failitus," then you could conceive of circumstances where the capapcitor would periodically create a heavy draw condition, and then it would go away, then appear again for a little while, then go away and his amp gauge would show a big positive current flow while it was doing that. Now granted, that's a stretch, but possible....